721137440 has 48 divisors (see below), whose sum is σ = 1706193720. Its totient is φ = 288030720.

The previous prime is 721137413. The next prime is 721137463. The reversal of 721137440 is 44731127.

It can be written as a sum of positive squares in 4 ways, for example, as 528816016 + 192321424 = 22996^2 + 13868^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 120110 + ... + 125970.

Almost surely, 2^721137440 is an apocalyptic number.

It is an amenable number.

721137440 is an abundant number, since it is smaller than the sum of its proper divisors (985056280).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721137440 is a wasteful number, since it uses less digits than its factorization.

721137440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6645 (or 6637 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 29.

The square root of 721137440 is about 26854.0023087807. The cubic root of 721137440 is about 896.7526758996.

Adding to 721137440 its reverse (44731127), we get a palindrome (765868567).

The spelling of 721137440 in words is "seven hundred twenty-one million, one hundred thirty-seven thousand, four hundred forty".